Fusing optical communication and lasers. Using fiber-optics to achieve a resurgence in Japan's industrial lasers.

What are optical fiber lasers?

To explain the mechanism of optical fiber lasers in a way that is easy to understand, optical fibers are placed in a ring configuration, and by repeatedly sending light through the ring, a laser is created. Conventionally, lasers are made by combining mirrors or lenses in many layers and propagating light through those mirrors or lenses. But in lasers that use optical fibers, all the light is propagated through the fibers, thereby allowing the manufacture of strong lasers with extremely high stability. Lasers can be made that are even easy to use, for example, in industrial fields with harsh environments such as high temperatures or vibration.

The theme of our optical fiber laser research

Optical fibers are extremely fine, so compared to a laser that emerges from a bulk of glass, the cross-sectional area that amplifies the light is unavoidably smaller, and just one fiber can't produce a large amount of energy. So, in our laboratory, by bundling multiple fibers together, we have been working to develop the kind of laser that can produce large-scale energy.
We are also researching how to impart special abilities to light that emerges from optical fibers.

Future prospects of optical fiber lasers

Currently, because the output of optical fiber lasers is not high, the first field of their application is measurement. We hope they can be used to measure exact distance, or that the interference of light can be utilized to accurately measure the shape of an object. After that, we want to apply them to a Japanese field of expertise—the manufacturing industry. We aim to expand the usage range to product processing sites in areas such as the automobile industry and electronics industry, as two, easy-to-understand examples.
To be frank, Japanese industrial lasers do not have the momentum they once had. Among industrial-use ones, Germany is much more advanced. Luckily, Japan possesses very advanced technology in the field of optical communications and in fiber-optics technology cultivated in optical communications. By joining together these technologies, we believe it is possible to develop laser equipment with never-before-seen functions. We hope to contribute to industry in this way.

New discoveries born from failure

Since our research is focused on experiments, we first study existing research results. But, there are many things in those writings that we will only understand by performing the experiments ourselves. As we perform experiment after experiment, there will be many failures. If we fail, I hope we can consider that in doing so we have surely discovered something that was not contained in the written research results. Discoveries are sometimes made when we have difficulty. As a researcher, I hope to foster that disposition in my students.

Minoru Yoshida
Professor, Department of Electric and Electronic Engineering

Affiliation: Department/ Electric and Electronic Engineering, Graduate school/ Electronic Engineering
Laboratory: Fiber Optics Laboratory

After graduating from Osaka University Graduate School, conducted research into fiber-optics at a manufacturing company.